Floatation and size classification of solids



May 30, 1967 EVANS ET AL 3,322,272

FLOATATION AND SIZE CLASSIFICATION OF SOLIDS Filed June 24, 1964 s Sheets-Sheet 1 INVENTORS Faster .0. [1/900 BY H4 1: l/zfiqwm/qdq ZQMQLMLW May 30, 1967 Filed June 24, 1964 R. D. EVANS ET AL FLOATATION AND SIZE CLASSIFICATION OF SOLIDS 3 Sheets-Sheet 2 A WOF/YU May 30, 1967 D EV ET AL 3,322,272

FLOATATION AND SIZE CLASSIFICATION OF SOLIDS Filed June 24, 1964 3 Sheets-Sheet 5 Ti E.

yoPa-fivwmr/c 7,97 (Fm 5 5/004) 1 507747704 A/YD i1 GMSS/F/CAWO/Y United States Patent ()fifice 3,322,272 Patented May 310, 1%67 3,322,272 FLOATATION AND SIZE CLASSIFICATIGN F SOLIDS Robert D. Evans, Pierce, and Harvie W. Ereathitt, Jia, Lakelnnd, Fla., assiguors to Qontinentai Gil Company, Ponca (Iity, 0141121., a corporation of Delaware Filed June 24, 1964, Ser. No. 377,569 4 Claims. (Ci. 209-12) This invention relates to floatation and size classification of the non-float fraction of solids in divided form, and more particularly relates to simultaneous pneumatic and hydraulic operations upon particles of various classes of size for the purpose of separating out the floatable fraction and classifying the non-float fraction by size classes.

In the recovery of phosphates from phosphate and silica bearing ore, it has been the practice to employ an initial sizing step separating the portion of the ore termed phosphatic sand into fines and coarse feed, followed by separate operations upon the two fractions. Typically each fraction would be subjected .to a rougher floatation step with anionic floatation reagents, followed by acid deoiling, rinsing, and then a second floatation step wherein the product of both the fines and coarse branches of the previous steps are treated together with cationic floatation reagents which float away the remaining fine silica contaminants.

The use of two rougher floatation circuits, one each for the fines and the coarse, is inherently wasteful and was heretofore justified only by the addition to B.P.L. (bone phosate of lime) recovery added by separately treating the coarse fraction. It has always been recognized by the art that a single rougher floatation circuit which did not sacrifice B.P.L. recovery with respect to the above described multiple circuit arrangement, would be much preferred and very advantageous from the economic and operating standpointsv It is accordingly a principal object of the present invention to provide means for recovering in a single circuit mineral particles from sand-like ore containing solid contaminants.

Another object is to provide such a means in the recovery of phosphate from so-called phosphatic sand containing silica and/ or other waste contaminants.

Another object is to provide a mineral recovery means that requires less equipment and is more economical to employ.

Another object is to provide apparatus capable of extracting suflicient B.P.L. values in a single rougher floatation operation so that separate treatment of fines and coarse fractions is not necessary.

Yet another object is to provide a single floatation and size classification cell employing combined pneumatic and hydraulic means and capable of a high degree of B.P.L. recovery when operated upon feed-stock including a wide range of particle sizes.

These and other objects and advantages of the invention will be better understood as the description of one embodiment of the inventive principles proceeds, in con junction with the drawings, wherein:

FlGURE 1 is a somewhat schematic view of an apparatus according to the invention, illustrating the apparatus as if in vertical cross-section, so as to show the internal details thereof,

FIGURE 2 is a block diagram of a series of process steps according to the present invention which steps may be carried out by the apparatus of FIGURE 1, and

FIGURE 3 is a block diagram of a phosphate ore recovery process utilizing the apparatus of FIGURE 1.

Briefly, the present invention contemplates reagentizing a ulp containing mineral value particles and waste contaminant particles (e.g., silica) so that one of them (e.g., the mineral value particles) is floatable and the other is non-floatable. The reagentized pulp is then passed into a single body of water whereby turbulence (e.g., by Waterjet action) the particles are separated for descent therein. Within the body of water is a plurality of sources of air bubbles, and the ascending bubbles pass the descending particles in intimate countercurrent contact. The floatable particles (e.g., the mineral values) appear at the surface of the body of water for collection. The still descending non-floatable particles are subjected to hydraulic classification so that one or more size fractions are available for collection, depending upon preference,

Referring now to the drawings, the apparatus according to the invention comprises a main tank indicated generally at it having an upper cylindrical portion 11 and a lower 'frusto-conical portion 12 tapering downwardly from the cylindrical portion to meet a lower hindered settling column 13, below which is situated a lower cylindrical portion 14 of somewhat greater diameter than portion 13. Within the tank 10, and coaxial with it, is an inverted cylindrical tank or vessel 15, constituting the upper or free-settling column in the apparatus, mounted by appropriate means (not shown), and having a closed upper end and a lower open mouth 16 spaced above the cylindrical portion 13, and being at least as great and preferably greater in diameter than said portion 13.

At a lower region in the cylindrical portion 14 of the hindered-settling column, means 17 are provided for the continuous introduction of water in considerable quantity, said water being introduced tangentially to portion 14. Within the portion 14, immediately above the locality of introduction of water, is a so-called constriction plate 18 separating the lower region 19 of portion 14 from the upper region thereof; this plate has multiple perforations of suitable size, through which the water introduced by pipes 17 flows with considerable velocity, to rise in the column 13 and provide hindered-settling conditions there in. For purposes of drainage at desired times, a valved pipe 20 (normally closed) extends downwardly from the constriction plate 18 to a region below the portion 14.

To provide a discharge at the top of the upper column 15, a short pipe length 21 (with its axis vertical), having a plurality of side openings for entrance of liquid is mounted directly beneath the closed upper end of the column. From this inlet device 21 a siphon type discharge 22, suitably valved, extends to a convenient discharge location (not shown) outside the tank lit, for removal of liquid rising in the upper column 15.

Another discharge instrumentality opens within the portion 14, above the constriction plate 18. Although this discharge means may be of various designs, a presently preferred form, as illustrated, comprises a float-valve controlled siphon system. It includes an enlarged lower section 23, opening downwardly and connected at its upper end with a long pipe section 24 extending upwardly to a predetermined location above the tank 1%, where it communicates with a further pipe section 25 extending beyond the tank and thence to a suitable discharge location (not shown).

Opening downwardly in the portion 14- at about the level of the section 23, a pipe 26, providing a hydrostatic column, extends upward and communicates at its upper end with the bottom of a float valve chamber 2'7 located a predetermined distance above the tank it) and above the horizontal portion of the pipe 25. The chamber 27 at its top communicates with the atmosphere through a vent-tube 28, and also with an air-vent tube 29 which in turn opens into the junction of pipes 24 and 25. Within the chamber is a float valve element 3i which upon floating upward, closes air-vent tube 29.

This float valve is so positioned in relation to the surface 31 of liquid in the tank 10 that. it will close when the pressure in the locality of the lower opening of the pipe 26 is greater than normal liquid pressure at that region by a predetermined amount, representative of a certain particle density, in that locality. That is, when liquid rises, due to the artificially increased fluid density caused by a condition of teeter in the portion 14, to a predetermined level in the hydrostatic column above the level 31 of fluid in the tank It), the valve 30, which is positioned at that predetermined level, closes, thereby sealing the siphon pipes 24, from the atmosphere and permitting siphon action to effect discharge of particlebearing liquid from the portion 14. A supplemental flow of water is introduced into the lower siphon section 23 through a priming pipe 32 to facilitate the initiation of this siphon action.

An annular froth overflow launder 33 is disposed at the upper outer wall of tank 10. The outer rim 34 of launder 33 is disposed somewhat higher than the adjacent rim 35 of tank 10, which in turn is at the level 31 of the liquid in the tank 10, that is to say, tank 10 is filled to tank rim 35. Launder 33 has a shallow side and a deep side, both as illustrated, and sloping intermediate portions. At the deep side, shown on the left in FIGURE 1, is provided a froth Withdrawal pipe 36 adapted to empty launder 33 of its contents and to discharge same to a discharge location (not shown).

Atop free-settling tank 15, but not communicating therewith, is feed-well 37, which is generally cylindrical in outline and of the same diameter as tank 15. Spaced at regular intervals around the lower portion of feed-well 37 is a plurality of holes 38. The upper end 39 of feedwell 31 is open, and the upper edge or rim 4% lies slightly below the level 31 of water in tank 10, that is to say, slightly below the height of rim 35 of tank 10. Disposed within feed-well 37 at the bottom thereof, and at a coaxial diameter somewhat less than that of feed-well 37, is a circular coil of pipe'dl, having a multiplicity of very fine holes in the wall thereof, for a purpose to be hereinafter described.

Situated below the feed-well 37, at about the intermediate level of tank 15, is a plurality of circular coils of pipe 44. At least one circular coil is disposed inwardly near the wall of tank 15, while at least one other is located outwardly near the wall 12 of tank 10. Each coil contains a multiplicity of minute perforations, and the plurality of coils are interconnected for the passage of air from one to another.

Leading in from a source of low pressure air supply (not shown) is supply pipe 46 which divides into separate sub-supply pipes 47 and 48. Pipe 47 proceeds down along the outside of walls llll and 12 of main tank '16, being suitably secured thereto, until it branches into header 47a which feeds air under pressure to pipe coils 45 and 43. Header 47a is valved at 471). Sub-pipe supply pipe branch 48 proceeds over to feed-Well tank 37, through valve 48a, thence downwardly in feed-well 37 to attach to and communicate its pressurized air to pipe coil 41 at the bottom of feed-well 37. Valves 47b and 48a may be manual or automatic as desired.

Located above feed-well 37, and slightly above the level of water 31, that is to say, slightly above the level of rim 35 on main tank 10, is a complex of waterjet pipes 49. All of the pipes comprising the complex are situated within the area described by the opening 33 of feed-well 37, but somewhat thereabove, as already mentioned. The individual pipes in the complex 49 may be arranged in a concentric circular array, or in a parallel grid array, or in other arrangements. In each event, the aforesaid area of opening 39 will be covered with a uniform areadensity of water pipes of complex 49. Each individual pipe has on its underside, directed downwardly at feed-well 37, a plurality of small diameter waterjet orifices, and each pipe in the complex is interconnected with each other pipe in the complex. Leading in from a source of supplementary water (not shown) is a supply pipe 50 which connects with, and supplies water to, the waterjet pipe complex 49.

A feed-pulp supply pipe 51 leads in the pulp to b classified, and deposits it into feed-well 37 at a central location within opening 39 and preferably slightly below the level of water 31. By way of example, phosphate ore from which most of the particles larger than 14 mesh have been removed (as in so-called washer operation of conventional sort), can be supplied as feed by supply pipe 51 in the form of aqueous pulp of convenient dilution; inasmuch as factors of solids concentrations, amounts of water in various supplies and the like may be selected in the same manner as for previous double-column classifiers, these aspects of the feed-stock introduction will no be discussed here. However, it is essential that the feedstock be previously deslimed and floatation-reagentized in an appropriate manner to be discussed more fully hereinbelow, so the phosphate floatation recovery may be carried out by the present apparatus. Moreover, it is to be understood that while floatation recovery of phosphate is described and primarily intended herein, the principles of operation apply also to other floatable mineral ores when supplied in pulp form with admixed silica or th like solid contaminants. It will be remembered that in the present discussion the phosphate fraction is reagentized to be the floatable fraction while the silica fraction is noniloatable. As will be illustrated hereinbelow, the reagent can be chosen to reverse this relationship.

In operation, the tank 10 is filled with water to the level 31, that is to say, to the level of rim 35, and feed pipes 46, 50, 17, and 32 are brought into play so as to deliver their respective fluids to tank 10. When appropriate balance of the various feeds is attained, feed supply pipe 51 is caused to introduce into feed-Well 37 an aqueous pulp of phosphate ore having particles very predominantly below 14 mesh in size, as aforesaid, and reagentized so as to float the phosphate particles.

The downwardly directed jets of water emanating from pipe complex 49 deeply penetrate the water volume within feed-well 37. The entire inner volume of feed-well 37 is thereby characterized by a region of high fluid jets coexisting with adjacent relatively motionless bodies of water. Since the waterjets are closely and uniformly distributed, the areas of shear are similarly placed. In addition to producing uniformly distributed fluid shear, the aforesaid jets of water also entrain air which travels downwardly as streams of fine bubbles in feed-Well 37 so as to be concurrent with the descending pulp particles from feed-pipe 51, which bubbles then reverse direction when the fluid jet momentum has been spent, and travel upward countercurrent with the descending pulp particles,

but in a more diffused pattern of bubbles. That is to say,

as far as the jet produced bubbles are concerned, they are in segregated streams going down, and are in diffused streams tending to fill the volume of feed-well 37 going back up. The pulp particles are thus subjected to fluid shear on their way down in feed-well 37, in addition to concurrent scrubbing with fine air bubbles. These operatrons tend to separate the particles and expose them to air bubbles. These combined processes are of course concurrent and continuous. Another function of the waterjets from pipe complex 49, that is to say in addition to fluid shear and dual action bubble streamlets, is to supply the supplementary water required to continuously wash the phosphate froth product appearing at the surface 31 into launder 33, as hereinafter described.

At the bottom of feed-well 37 is circular pipe section 41 as aforesaid. The purpose of this section 41 is to suuply additional air bubbles in feed-well 37. Before the particles emanating from pipe 51 ever reach the bottom of feed-well 37, a large proportion of them are floated by the aforesaid air bubbles, and the burden deposited at the bottom of feed-well 37 will therefore largely be the non-floatable material originally contained in the influx of pulp at the orifice of feed supply 51.

Those particles that are not floated by the bubbles within feed-well 37, crowd out to the outer bottom edge of feed-well 37, that is, to the outer annulus containing holes 38. These particles pass through holes 38 and are evenly deposited into the annular space between tank and wall 11. Sub-supply pipe 47 is all this while supplying air under pressure to circular pipe sections 43 and 45 as aforesaid. These pipe sections 43 and d5 produc a great many fine bubbles similar to that described with regard to pipe section 4-1 aforesaid. Any particles descending in the annulus between tank 15 and wall 11 must pass through the bubbles produced by pipe-sections 43 and 45 and this constitutes a still further opportunity for any remaining floatable particles to be floated away. Thus during the free-fall the remaining floatable particles are subjected to another countercurrent bubbling with air, and of course any particles floated during the total descent in the annulus between tank 15 and wall 11 appear at surface 31 as a froth. The froth appearing at surface 31 comprises virtually nothing but floatable particles (in the present example being the phosphate fraction), and when spilled over rim into launder 33, the froth may be collected by pipe 36.

The non-floated particles that pass the region of circular pipe sections 43 and settle downwardly thereafter into the region between hindered settling column 13 and free-settling column 15. At that region the particles come under the influence of the said two columns, and thus as particles accumulate within hindered settling column 13, the action of the water introduced by pipes 17 through constriction plate 18 is to build up a condition of teeter in the said mass of particles within column 13, producing in effect a higher fluid density, and establishing hindered settling in that column. Hence essentially only the larger or faster-settling particles can travel all the way down in column 13 to the siphon inlet 23, there to be withdrawn via pipe 24-25, the float valve 30 having closed off the vent tube 28 from access to the siphon circuit 24-25, in consequence of the increased hydrostatic pres sure at the region of siphon inlet 23 due to the increased apparent density just mentioned, and as monitored by hydrostatic column pipe 26. The finer or slower settling particles, unable to descend in the column 13, are car ried upward by the flow, into the upper column 15 and thence through the siphon means 21-22 to discharge.

In accordance with the advantages of the invention, the particles initially entering the region between hindered settling column 13 and free-settling column 14 are so devoid of floatable phosphate particles (in the present illustration wherein the phosphate is the floatable fraction) that the fine fraction taken oil? at siphon 21-22 comprises all silica and other waste contaminants, while the coarser fraction taken otf at siphon 23-24-25 comprises nearly all silica and other contaminants, together with a small portion of larger phosphate particles. As will be further pointed out hereinbelow, the small amount of phosphate particles there contained could be ignored altogether without reducing the overall efliciency of recovery of the apparatus below a highly acceptable level. However, it is a feature of the invention that the small amount of phosphate not floated appears in the coarse fraction alone, and thus reduced in silica contamination, can easily be scavenged in a subsequent well understood operation if desired, or otherwise reclaimed.

It should be understood that while the floatation of phosphates by the use of a suitable floatation reagent which floats the phosphate particles and does not float the silica and other waste contaminant particles has been described above by way of example, the apparatus is equally useful in the floatation of silica and the like contaminants by the use of a suitable floatation reagent which floats the silica particles but does not float the phosphate particles. In general anionic reagents float the ore values, and cationic reagents float the Waste contaminants. It is common in phosphate ore extration processes to employ first an anionic floatation step to float away the phosphate, and then to employ, after suitable intermediate treatment, a cationic floatation step to rid the phosphate of any lingering fine silica contamination. The present apparatus may be employed for each of these stages by merely providing the appropriate reagents and by correctly identifying the source of product and the source of tailin In the anionic stage the froth is the product as already illustrated, while in the cationic stage the froth contains silica and is waste and the product appears at the two siphons if sized product is desired, or at lower siphon 23 if unsized product is wanted, and water to pipes 17 is stopped and siphon 212 valved shut. Thus a series of two apparatuses according to the invention may be employed, one in the initial anionic floatation stage, and a second acting upon the product of the first, in a cationic floatation stage.

Referring now to FIGURE 2, the process eflectuated by the apparatus of FIGURE 1 comprises an initial step of reagentizing the phosphate ore pulp with a suitable floatation reagent, for example if anionic floatation is desired, with a fatty acid, or if cationic floatation is desired, with an amine. The nature of the floatation reagent, whether it is anionic or cationic, will determine whether the phosphate or the silica (or other waste) is floated. In either event the reagentized pulp is then subjected to the step of immersion in a liquid bath for descent therein while being subjected to liquid turbulence and air bubble action. A large proportion of the floatable particles will be floated immediately during this step. Any non-floated pulp remainder is then subjected to continued descent in the liquid bath while being subjected to further bubble action as required to give all reagentized particles a chance to attach to an air bubble. The total floated fraction is collected. The non-float fraction after the last bubbling step is subjected to the step, of continued descent into a region of teeter wherein the particles are divided on the basis of size into those that descend for possible collection and. those that ascend for possible collection. One or more of these fractions may actually be collected.

The exact nature of the final collection step depends on whether an anionic or a cationic reagent has been employed. When an anionic reagent has been employed, the floated particles are the principle phosphate product, and the fine non-floated fraction may be discarded as for all practical purposes being all silica. The coarse non-float fraction will be collected either for subsequent scavenging of the minority of phosphate particles or for discard, depending upon particular preferences. In usual practice the coarse tailings can be discarded without appreciable sacrifice or overall recovery. On the other hand, when cationic reagents are employed the floated fraction is fine silica and is discarded, while both the fine and coarse non-float products are heavily phosphate bearing and will be collected. Normally cationic reagents will only be used on a pulp that has already been greatly enriched in B.P.L. in a previous operation, as for example by an anionic operation as above, and consequently both the fine and coarse non-float fractions will be nearly all phosphate, although the condition of separation thereof is nevertheless beneficial since the fine fraction will have even higher B.P.L. due to the greater possibility of silica particles included within phosphate particles which prevails with the coarser fraction.

Referring now to FIGURE 3, an overall flow-sheet and process for the recovery of phosphate values from phosphate containing ore according to the present invention comprises presenting dislim'ed phosphate mineral aqueous pulp of less than 14 mesh size particles, reagentizing the said pulp with an anionic floatation reagent, and charging the resulting reagentized aqueous pulp to the apparatus of FIGURE 1, hereinafter in regard to IGURE 3 identified as a hydro-pneumatic floatation and classification apparatus. Suitable quantities of water and air are also charged to the apparatus, and the fine tailings collected by pipe 22 of FIGURE 1 are discarded since they are all, or very essentially all, silica. The

coarse fraction collected at pipe may, as already mentioned, be treated in alternative manners depending upon local needs and preferences. As shown in FIGURE 3, the coarse fraction, when it is either very low in phosphate values, or when it is determined that overall recovery efliciency is not imparied appreciably by the small amount of phosphate in that fraction, may be discharged as waste to a debris location. Alternatively, when any of the opposites of the criteria just mentioned prevail, or when for other reasons scavenging is favored, that coarse fraction may be fed to scavenging equipment of any desired type, and there recovered and either segregated as a separate product or contributed to the total product, as hereinafter described.

The froth product from the hydro-pneumatic floatation and classification apparatus just mentioned, of course includes very nearly all the phosphate values in the original pulp, and includes also, sometimes, some fine silica material. Alternatively, this froth product can, therefore, be recovered as product directly upon rinsing and dewatering, or it can be further processed to remove any fine silica residual contaminant, both as shown in FIGURE 3. If the material is to be further treated, it will also be rinsed and partially dewatered, treated with a mineral acid to remove the previous floatation reagent, then treated with a cationic floatation reagent and fed to a second hydropneumatic floatation and classification apparatus according to the invention, together with suitable quantities of water and air.

In the second, or just mentioned, apparatus the froth constitutes the previously described fine silica contaminant remaining, possibly, on the phosphate product of the previous stage. The froth of fine silica goes as waste to debris. Two fractions, a coarse and a fine, of phosphate particles are produced. In some operations it may be desirable to combine them, as is shown in FIGURE 3, with the phosphate product of the scavenger as a final total phosphate product. In other operations it will be desirable to keep the products separate. Thus the fine fraction of the stage just mentioned is higher, typically, in phosphate values than the coarser stage. It is accordingly a feature of the invention that various sized and valued fractions of the product are segregated which may or may not be utilized separately.

It will be apparent that the present apparatus, process, and resultant flow-sheet greatly simplify the previously employed two circuit approach, which required sizing into two fractions followed by separate anionic floatation circuits upon the separate fractions (or alternatively to the I coarse circuit, mechanical separation techniques) follow- Example N0. 1

The 6 mesh conditioned feed which had been reagentized with anionic reagents was supplied to a hydropneurnatic floatation classifier of the type illustrated in FIG. 1 into the feed-well. The top of the feed-well was slightly below the water overflow level of the hydrosizer tank. As the feed fell into the well the conditioned phosphate particles in the feed adhered to the air bubbles and rose to the surface and out and over the tank overflow. Particles which did not float immediately as well as the unreagentized particles (including silica) dropped into the bottom of the well and passed into the main hydrosizer tank through the outlet holes at about the bottom of the feed-well. The air bubbles from the lower air lines within the tank and beneath the feed-well gave the re agentized non-floated particles another chance to float to the surface and be skimmed off and recovered. The coarse sand, fine sand and all phosphate particles both coarse and fine which were not reagentized sufiiciently to float in the upper portion of the tank drop or enter into the sorting zone or the space between the upper free settling column and the lower hindered settling column of the tank. The finer fractions were then picked up and carried out by the upper column system. The coarse fractions made up of silica and phosphate ended up in the lower column and were siphoned out periodically by the automatic siphon system.

In the above-described test the sizer float, i.e., reagentized particles floating in the tank overflow were relatively free of silica assaying 71.16% B.P.L. and 4.61% by weight insoluble. The upper column tails, i.e., the floatclass or fine discharge, were generally very fine, made up of mostly silica having a particle size such that 99% by weight measured mesh. Some reagentized phosphate agglomerates were noted in the upper column tails. The coarse discharge product was tabled without the use of additional reagents to obtain the table concentrate and the table tail noted below. The pertinent test data in connection with the operations are set forth in Table I herein below:

TABLE I Percent B.P.L. Percent Insol.

Feed to Floatation-Classificr 33. 69 53, 05 Float-Class. Coarse Diseh.:

Table Cone 63.92 6.86 Table Tails 5. 39 Float-Class. Fine Dis 1. (upper co 7. 60 Float-Class. Froth Prod. (Float) 71.16 4.61

SCREEN AND CHEMICAL ANALYSES OF SAMPLES +14 Mesh 14 +35 Mesh 35 Mesh Sample Percent Percent Percent Percent Percent Percent Percent Percent Percent Wt. .P. Ins. B.P.L. Ins. Wt. B.P.L. Ins.

Feed to Floatation Class 9. 4 6. 37 8. 29. 7 48. 90 33. 32 Gilt) 21. 22 69. 56 Float-Class. Coarse Disch. 23.5 66. G4 47. 0 40. 58 29.5 14.2 Float-Class. Fine Dlsoh. (Upper C01.) Trace 1.0 99. 0 2 7. 60 Float-Class. Froth Prod. (Fl0at) 4.4 43. 2 71.81 3. 52.4 70.79 5. 34

1 This is a size analysis prior to the table separation. 2 This analysis includes the 1.0%+35 mesh material.

9 Example N 0. 2

The practice of this invention was again applied to a feed substantially the same as the feed described hereinabove and employed in connection with the operations set forth in Example No. l. The pertinent test data are set forth hereinbelow in Table 11.

lift of potash ores and the like. In the treatment and upgrading of phosphate rock, ideally the apparatus and procedures of this invention would produce an upper column tailing with substantially no values or low enough to be discarded directly to waste. The apparatus and procedures of this invention should float ed the bulk of the floatable material. It may, however, be necessary to scavenge both the TABLE II.DISTRIBUTION OF TOTAL TEST PRODUCTS Percent Percent Percent Sample Percent Wt. B.P.L. is. B. P.L.

Distribution Feed to FloatationCl-nss 100. (J 28. 23 61. 17 100.0 Float-Class. Coarse 'Diseh 47.8 51 53.18 57.1 FloatClass. Fine Disch. (upper co 40.2 8.84 12.6 Float Class. Froth Prodv (Float) 12.0 70.97 5. 54 30.3

Analytical B.P.L. (Cale. head was 28.09% B.P.L.).

SCREEN AND CHEMICAL ANALYSIS OF SAMPLES +14 Mesh 14 +35 Mesh -35 Mesh Sample Percent Percent Percent Percent Percent Percent Percent Percent Percent Wt. B.P.L. Ins. Wt. l3.P.L. Ins. Wt. B.P.L. Ins.

Feed to FloatClass 17. 6 67.41 10. 41 43.0 32. 10 56. 90 39. 4 Float-Class. Coarse Diseh 30. 6 65. 60 12. 60. 9 20. 57 70. 42 8. Float-Class. Fine Disch 1.6 (Comb. 14 29.0 21. 05 a. 69.4 Float-Class. Froth Prod. (Float) 24.1 69.92 I 5.65 64.6 72.09 4.40 11.3

The +14 mesh fraction combined with -14 +35.

FLOATA'IION AND TABLE TESTS 0N COARSE DISCH. AND FINE DISCHARGE [Note: No additional reagents added to these prior to floatation] Table Test on Float-Class. Coarse Disch.

Table Concentrate Table Tailing Percent Percent Percent Percent Percent Percent Wt. B.P.L Ins. B.P.L. Percent Wt. 13.1. B.P.L.

Dist. Dist.

16. 5 69. 69 7. 48 17.0 1. 4 7e. 4 s7. 41 s. 34 76.1 76. 0 28 9 7. l 65. 35 14.48 6. 9 22. 6 2. 97 12. 1 100.0 67. 64 9. 38 100.0 100.0 5. 53 100. U

Floatation Test on Float-Class Fine Discharge Floatation Concentrate Floatation Tailing Percent Percent Percent Percent Percent Percent Wt. B.P.L. Ins. B.P.L. Percent Wt. B P.L. B.P.L..

Dist. Dist.

+ Mesh G9. 92 6.15 79. 2 s. cs 67. 5 23. 4 60.10 20. 36 20. 8 73. 7 1.49 32. 5 100. 0 67. 62 9. 48 100. 0 100.0 3. 38 100. 0

Note: The fine teed used in this test (Feed to Float-Class, cell was half fine cell feed and half belt feed) was very low in B.P.L content and partially accounts for the fact that only 12.0% weight fioatated ofi in the sizer Heat.

The results of the tests described in Examples I and II and the data obtained therein indicate that the hydrosizerfloatation apparatus of this invention is useful and presents very valuable prospects for applicability to the treatment and upgrading of solid materials, particularly phosphate rock. The flotation classifier apparatus of this invention and the operating procedures therewith are usefill in many types of hydro-metallurgical operations. Specifically, in addition to the treatment and upgrading of phosphate rock the apparatus and procedures of this innon-floating fractions recovered from the flotation classifier apparatus of this invention. If necessary, the upper column tailings could be re-floated in a second floatation classifier or in a conventional type floatation cell. This material, the upper column tailings, Would appear to be perfectly sized for this operation. Also, the coarse sizer product removed from the apparatus of this invention would have a large portion of the floatable fraction removed and this product would also be properly sized for additional, subsequent concentrating steps, if desired.

vention are also useful for the treatment and upgrading As will be apparent to one skilled in the art in the TL 1 light of the foregoing disclosure many modifications, substitutions and alterations are possible in the practice of this invention without departing from the spirit or scope thereof.

What is claimed is:

1. Apparatus for classifying a liquid flotation reagentized pulp of mineral value particles admixed with waste particles into a floated portion highly enriched in one kind of said particles and a non-floated portion highly enriched in the other kind of said particles, the non'floated portion being further classified into fractions on a particle size basis, comprising means adapted to accommodate a single body of liquid, feed well means provided in the upper portion of said body of liquid, said feed well means be ing provided with a bottom outlet, means for introducing said reagentized pulp into said feed well means, means for creating turbulence and fluid shear in the region of introduction of said reagentized pulp within said feed well means, first means for producing a supply of fine air bubbles within said feed well means below the region of introduction of said reagentized pulp for flotation of said reagentized floatable particles, hydraulic classifying means located at a lower portion of said body of liquid comprising upwardly open lower column means, spaced opposed downwardly open upper column means, said columns defining therebetween means for the entrance of non-floated particles descending from above, second means producing a supply of fine air bubbles in the portion of said body of liquid surrounding said upper column means and positioned intermediate said first means for producing a supply of fine air bubbles and the opening of said upper column means, liquid supply means at said lower column means for moving liquid from said lower column means to said upper column means, means for removing faster-settling particles from said lower column means, and means for removing slower-settling particles from said upper column means.

2. Apparatus for classifying a liquid flotation reagentized pulp of mineral value particles admixed with waste particles into a floated portion highly enriched in one kind of said particles and a non-floated portion highly enriched in the other kind of said particles, the non-floated portion being further classified into fractions on a particle size basis, comprising means adapted to accommodate a single body of liquid; feed well means provided in the upper portion of said body of liquid, said feed well means provided with a bottom outlet, means for introducing reagentized pulp into said feed well means, means for creating turbulence and fluid shear in the region of introduction of said reagentized pulp within said feed well means, first means for producing a supply of fine air bubbles within said feed well means below the region of introduction of said reagentized pulp for flotation of said reagentized floatable particles, hydraulic classifying means located at a lower portion of said body of liquid comprising upwardly open lower column means, spaced opposed downwardly open upper column means, said columns defining therebetween means for the entrance of non-floated particles descending from above, second means for producing a supply of fine air bubbles in the lower portion of the body of liquid surrounding said upper column means and intermediate said first means for producing a supply of fine air bubbles and the opening of said upper column means, liquid supply means at said lower column means for moving liquid from said lower column means to said upper column means, means for removing fastersettling particles from said lower column means, means for removing slower-settling particles from said upper column means, and means for collecting the floated fraction appearing at the surface of said body of liquid.

3. Apparatus for classifying an aqueous flotation re agentized pulp of mineral value particles admixed with waste particles into a floated portion highly enriched in one kind of said particles and a non-floated portion highly enriched in the other kind of said particles, the non-floated portion being further classified into two fractions on a particle size basis, comprising a vessel adapted to be filled with liquid, upright hindered settling column means opening upwardly into communication with a lower part of said vessel and having liquid introducing means and first particle removal means at the foot thereof for effecting hindered settling of liquid carried particles contained in said column means and to accumulate particles of fastest settling characteristics for discharge through said first particle removal means, upwardly closed free-settling column means having sec-0nd particle removal means at the top thereof and disposed above said upright hindered settling column means and opening downwardly into communication with said vessel at a locality spaced above said upright hindered settling means for effecting freesettling of faster-settling particles in solids-carrying liquid movng upwardly in said upwardly closed column means and to separate and discharge particles of slowest-settling characteristics through said second particle removal means, feed well means disposed above said upwardly closed free-settling column means and within said vessel for the receipt of said reagentized aqueous pulp, said feed well means being provided with a bottom outlet, means for introducing said reagentized pulp into said feed well means, means for creating turbulence and fluid shear in the region of introduction of said reagentized pulp into said feed well means, first means for producing a supply of fine air bubbles within said feed well means, second means for producing a supply of fine air bubbles in the lower portion of the body of the liquid within said vessel and surrounding said upwardly closed free-settling column means positioned and intermediate said first means for supplying fine air bubbles and the opening of said upwardly closed column means and means for collecting floated particles from the surface of the liquid in said vessel.

4. Apparatus for classifying an aqueous floatation reagentized pulp of mineral value particles admixed with waste particles into a floated portion highly enriched in one kind of said particles and a non-floated portion highly enriched in the other kind of said particles, the nonfloated portion being further classified into two fractions on a particle size basis, comprising a vessel adapted to be filled with liquid, upright hindered settling column means opening upwardly into communication with the lower part of said vessel and having liquid introducing means and first particle removal means at the foot thereof for effecting hindered settling of liquid carried particles contained in said column means and to accumulate particles of fastest settling characteristics for discharge through said first particle removal means, upwardly closed free-settling column means having second particle removal means at the to thereof and disposed above said upright hindered settling column means and opening downwardly into communication with said vessel at a locality spaced above said upright hindered settling column means for effecting free settling of faster-settling particles in solids-carrying liquid moving upwardly in said upwardly closed column means and to separate and discharge particles of slowest settling characteristics through said second particle removal means, feed well means disposed above said upwardly closed free settling column means and within said vessel for the receipt of said reagentized aqueous pulp, said feed well means being provided with a bottom outlet, means for introducing said reagentized pulp into said feed well means, means for creating turbulence and fluid shear in the region of introduction of said reagentized pulp into said feed well means, said means for creating turbulence and fluid shear comprising water-jet complex means situated immediately above said feed well means and adapted to project a multiplicity of spaced, downwardly directed water jets for impingement onto the liquid surface within said feed well means, first means for producing a supply References Cited UNITED STATES PATENTS 2,416,066 2/1947 Phelps 209-168 2,569,141 9/1951 Bakels 20912 2,967,615 1/1961 Goin 209-12 2,967,617 1/1961 Evans 209158 FRANK W. LUTTER, Primary Examiner. 

1. APPARATUS FOR CLASSIFYING A LIQUID FLOTATION REAGENTIZED PULP OF MINERAL VALUE PARTICLES ADMIXED WITH WASTE PARTICLES INTO A FLOATED PORTION HIGHLY ENRICHED IN ONE KIND OF SAID PARTICLES AND A NON-FLOATED PORTION HIGHLY ENRICHED IN THE OTHER KIND OF SAID PARTICLES, THE NON-FLOATED PORTION BEING FURTHER CLASSIFIED INTO FRACTIONS ON A PARTICLE SIZE BASIS, COMPRISING MEANS ADAPTED TO ACCOMMODATE A SINGLE BODY OF LIQUID, FEED WELL MEANS PROVIDED IN THE UPPER PORTION OF SAID BODY OF LIQUID, SAID FEED WELL MEANS BEING PROVIDED WITH A BOTTOM OUTLET, MEANS FOR INTRODUCING SAID REAGENTIZED PULP INTO SAID FEED WELL MEANS, MEANS FOR CREATING TURBULENCE AND FLUID SHEAR IN THE REGION OF INTRODUCTION OF SAID REAGENTIZED PULP WITHIN SAID FEED WELL MEANS, FIRST MEANS FOR PROVIDING A SUPPLY OF FINE AIR BUBBLES WITHIN SAID FEED WELL MEANS BELOW THE REGION OF INTRODUCTION OF SAID REAGENTIZED PULP FOR FLOTATION OF SAID REAGENTIZED FLOATABLE PARTICLES, HYDRAULIC CLASSIFYING MEANS LOCATED AT A LOWER PORTION OF SAID BODY OF LIQUID COMPRISING UPWARDLY OPEN LOWER COLUMN MEANS, SPACED OPPOSED DOWNWARDLY OPEN UPPER COLUMN MEANS, SAID COLUMNS DEFINING THEREBETWEEN MEANS FOR THE ENTRANCE OF NON-FLOATED PARTICLES DESCENDING FROM ABOVE, SECOND MEANS PRODUCING A SUPPLY OF FINE AIR BUBBLES IN THE PORTION OF SAID BODY OF LIQUID SURROUNDING SAID UPPER COLUMN MEANS AND POSITIONED INTERMEDIATE SAID FIRST MEANS FOR PRODUCING A SUPPLY OF FINE AIR BUBBLES AND THE OPENING OF SAID UPPER COLUMN MEANS, LIQUID SUPPLY MEANS AT SAID LOWER COLUMN MEANS FOR MOVING LIQUID FROM SAID LOWER COLUMN MEANS TO SAID UPPER COLUMN MEANS, MEANS FOR REMOVING FASTER-SETTLING PARTICLES FROM SAID LOWER COLUMN MEANS, AND MEANS FOR REMOVING SLOWER-SETTLING PARTICLES FROM SAID UPPER COLUMN MEANS. 